Machine for decorating and coloring plastic articles



April 1956 L. J. KOVACH .ETAL 2,740,376

MACHINE FOR DECORATING AND COLORING PLASTIC ARTICLES Filed March 4, 1955 3 Sheets-Sheet 1 [FIG I III! INVENTOR. LESLIE J. KOVACH JAMES F. RUTLEDGE 7 LESLIE J. KOVACH 46 49 4 JAMES F. RUTLEDGE 55 33 April 3, 1956 J, KQVACH ETAL 2,740,376

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April 3, 1956 L. J. KOVACH EI'AL 2,740,376

MACHINE FOR DECORATING AND COLORING PLASTIC ARTICLES Filed March 4, 1955 s Sheets-Sheet s INVENTOR. LESLIE J. KOVACH JAMES F. RUTLEDGE United States Patent MACHINE FOR DECORATING AND COLORING PLASTIC ARTICLES Leslie J. Kovach, Fitchburg,

Leorninster, Leominster,

and James F. Rutledge, Mass., assignors to Foster-Grant Co., Inc., Mass., a corporation of Massachusetts This invention relates to a machine for the coating of articles with colored configurations. In particular, it relates to an automatic maskless machine for coating the surface of synthetic plastic so as to simulate natural shell.

Natural shell has long been a desirable material for the manufacture of ornamental objects because of its beauty. Such a material is characterized by irregular colored streaks or configurations in a translucent or transparent background. Because of the cost of such materials and the difficulty of processing there have been attempts to form the ornamental objects from synthetic plastics and simulate the natural shell or bone by surface ornamentation.

in a previously described method of simulation a clear plastic such as polystyrene is color-coated on one surface by the use of a solvent type lacquer and a mask in which openings have been cut to simulate natural configurations. In using this method the articles or a small number thereof, such as a clear plastic comb, are placed in the mask, and then the lacquer or paint is applied through the mask openings by an operator with a spray gun. After applying the coating the mask is opened, the articles removed and the mask cleaned with paint solvent before re-using.

The chief disadvantages of the mask method of simulation are that masks require unloading after each application and mask-cleaning is frequently required between loadings, with the result that much lacquer and cleaning fluid is wasted. Only one color can be applied at a time with one mask. Also, masks are expensive and must be specially and precisely constructed for each particular article to be colored. In addition, the mask method is not suited to automatic operation with the result that it is done by hand with an attendant slow production rate.

In accordance with this invention it is possible to speedily, economically and automatically color plastic combs, sunglasses and other articles so as to simulate natural shell.

The essence of this invention consists in providing a skeleton belt equipped with means for holding the objects a fixed position and movingthe belt through a zone in which the articles are decorated in controlled lateral areas by one or more transversely oscillating downwardlydirected continuous streams of liquid colorants such as lacquer or paint. The combination of motion of the moving belt and the oscillating paint stream or streams produces a surface ornamentation closely simulating artificial shell. The process is completed by having the objects ejected onto a drying line.

In order to more clearly illustrate this invention a. preferred embodiment is described below and in the appended drawings adapted especially for combs and sunglasses but usable by slight adjustments for other articles. In this embodiment the moving skeleton belt is constructed of two parallel endless chains with a number of transverse rods on which clamping fixtures are mounted. The oscillation of each spray source is accomplished by a spring-backed transverse rod which follows an irregularly shaped rotating cam. In this particular embodiice ment there are three spray sources, each one adjusted to decorate a different longitudinal zone of the comb. A shield is provided for each fixture so that no washing of the fixture is required, the shield itself being automatically wiped of accumulated paint. Automatic ejection of the comb onto the drying line is also shown.

in the drawings:

Figure 1 illustrates a clear plastic comb before ornamentation;

Figure 2 illustrates the same comb after being decorated in accordance with this invention;

Figure 3 is a top view of the decorating portion of the machine showing the upper position of the skeleton belt and the spraying structures but for purposes of clarity not showing any structure below the belt;

Figure 4 is a longitudinal section looking from line 4-4 in Figure 3;

Figure 5 is a side View of an irregular cam engaging a cam wheel;

Figure 6 is a plan view of a fixture clamping a comb, but about to eject the comb onto a drying belt;

Figure 7 is an elevation of the fixture clamping a comb and about to eject the comb onto a drying belt;

Figure 8 is an illustration of the frames on which the skeleton belt and spray guns are mounted but omits the belts and spray guns and cams.

Figure 9 is a side elevation of the machine showing the general arrangement, driving means and cleaning means but omitting representation of the drying belt.

Referring now to Figures 3, 4 and 8, the machine is shown built on a support frame 26. Frame 29 has upper members 21 and 22, vertical members 23, 24, 25 and 26, and bracing cross members 27. On top of this supporting frame 2b is a spraying frame 10. The frame lll comprises front longitudinal member 11 supported by verti al members 13 and 14 attached to member 21 and rear longitudinal member 12 supported by vertical members 15 and 16 attached to member 22. Cross bracing members can be used, if desired, to give the spray frame it) increased rigidity.

Carried on the supporting frame and running along its top is an endless skeleton belt 3t} comprising two opposing parallel endless roller chains 31 and 32 between which are attached a series of flat transverse rods 33 by means of vertical chain plates Each chain is supported by separate gears 35, 35A and 37A. Front gear 35 is driven by a belt 36 connected via a roller sprocket 37 and roller belt 38 to a belt motor 39. The rods 33 are spaced sufficiently apart so that each can act as a support for an object-holding fixture to be described below.

On each transverse rod 33 is mounted a clamping fixture 40 which serves to hold an individual object which is to be decorated by the machine. A fixture comprises a stationary portion 41 and a movable portion 4-3. The stationary portion 41 is attached to the rod 33 and contains a lower fixed jaw 42 connected by a pivot 43 and a jaw spring 45 to an upper movable jaw 44. A pair of projecting pins 46 and 47 are provided on either side. The movable portion 43 is slidable on the pairs of pins 46 and 47 by its corresponding slots 49 on either side. The movable portion contains two ejector rods 51 and a shield 50 which protects the ejector rods and jaw assembly. The shield can be more or less extensive than shown, serving principally to cover the jaws and ejector rods, which if contaminated with paint, might smudge on the next succeeding object placed in the fixture. At the rear of the movable portion is a cam wheel 52 which is engageable with an exterior fixed cam 54 so as to cause the movable portion to slide away from the fixed cam, thus causing the ejector rods 51 to remove the object clamped by the fixture onto a drying belt 55. Return of the movable portion is provided by an ejector spring 53 connecting between the movable and fixed portions.

The spraying frame 1!} which contains the decorating zone has three oscillatory transverse spray-gun-support rods, 61, 62 and 63. One portion of each rod is borne in the front member 11, while the opposite end of the rod has a smaller section 64 borne in the rear longitudinal member 12. This rear end of the rod terminates in prongs 66 holding a cam wheel 67. Mounted between the larger cross section of the rod and the frame member 12 is a spring 65. It is so constructed that pressure upon the cam wheel 67 will cause the rod to move but removal of pressure on the cam wheel will allow the rod to return. Mounted on each rod in a desired position is a spray head 63 arranged to spray downwardly and vertically, the spray head being attached to the rod by a bracket as. he spray head is of conventional construction having a nozzle 7%, air line '71 and a fiuid line '72 leading from an exterior tank which is not shown. An air valve 73 and a fluid valve '74 serve to regulate the flow through the nozzle 7%).

The oscillatory motion of each rod assembly (51, 62 and 63) is controlled by a separate cam 92, all cams rotating on a single cam shaft 91 and supported by a cam frame 5. The shaft $1 is driven by a chain 93 connected to a motor 94.

Cleaning the fixture shields of paint deposit is accomplished by a wiping belt assembly which continuously removes any deposited paint to a solvent bath. The belt assembly 86 is composed of a cotton belt 81 running on an upper wheel 82 and a lower wheel 83. The lower wheel is partially immersed in a solvent tank 34 and is driven by a motor 85. The belt rubs against the shields.

The first adjustments usually made, are in the spray heads 68 and spray head brackets 69. Each head is placed in the proper position so that oscillation will allow it to cover a particular zone. Thus, as illustrated, in Figure 2, the adjustment as shown for rod assembly 61 covers the zone 101, rod 62 permits the coverage of zone Hi2, while rod 63 permits the coverage of the zone 103. It will be noted that each of the rods are similar but that the positions of the bracket 69 are different. As soon as the positions have been selected the paint tank or tanks (which are not shown) are filled, and by proper customary adjustment of air and fluid lines and valves, the paint is atomized through the nozzle 70 at a low air pressure. It is usually found best to atomize first and then cut out the air almost completely so that a thin but steady stream of paint is flowing from the nozzle. After each of these adjustments has been made, the paint is allowed to flow continuously and the cam motor 94 is started which causes the cams to turn and which in turn causes each of the rod assemblies to oscillate in a path whose dimension is determined by the shape of the cam perimeter. It should be noted that the typical cam surface as illustrated has peaks and valleys but that these are not equal. The intent is to simulate irregularity, although for some ornamental purposes a sinusoidal wave might be acceptable.

As soon as the spray assemblies and rods are in proper operation the other motors (39 and 85) are started and an operator feeds an article, such as a comb, into the jaws 44 and 45 of each fixture as it passes his position in the line ahead of the spray area. As a particular object clamped by its fixture moves into the spray zone encompassed by spraying frame 10, each rod assembly 61, 62 and 63 successively applies a somewhat irregular configuration to the different zones (101, 102 and 103) of the comb. After a particular article has passed out of the spray zone its fixture engages a fixed cam 54 mounted on the frame so that the cam wheel 52 causes the movable portion 43 to push its ejector rods 51 forward, thus throwing the article upon the drying belt 55. As a fixture moves around it comes in contact with the wiping belt and thus the shield is cleaned of any deposit of paint before returning for reinsertion of a new article to be painted.

The skeleton construction of the belt allows fumes and overspray to go through easily and presents little reflecting obstruction to the paint streams. For operator protection it is often desirable to provide a hood over the frame 10 and an enclosed duct immediately below leading to a suction fan, acting to draw out fumes and spray. These are not illustrated but are obvious to one skilled in the art.

The fixtures shown for holding the article cover by their jaws a small portion of the article. However, this does not alfect the final result since there are multiple clear areas in shell type ornamentation. The fixture shown is especially preferred because it automatically ejects, has a positive clamping action which is not disturbed by the pressure of the paint spray and permits just enough irregularity of insertion position by the operator to make the final products all slightly different in their final ornamentation.

As has been shown, each of the spray heads is mounted in a difierent position so as to cover a difierent longitudinally divided portion of the articles to be painted. The irregular oscillatory path provided by the opposing action of the cam and spring is regulated to form only a small path of travel. The relative speed of the skeleton belt and the oscillations are regulated so as to get the desired irregular ornamentation, each spray head covering a different longitudinal zone on the comb. In most cases the belt is moved much faster than the spray head in order to get streaks in a longitudinal direction.

it has been found that this maskless method is about four times as fast as the previously described mask meth ods. Further, with the embodiment described three different colors can be applied practically at once, either in separate zones as shown above or in overlapping zones. Each zone can be separately controlled to give the desired decoration. By changing spacing and position of the fixtures and spray heads, articles of many different sizes can be accommodated in the same machine.

The cams illustrated in the drawings have irregularly cut perimeters, in that the depth and breadth of valleys, and heights and breadth of peaks, are not uniform. They are so cut because regular-cut perimeters would give sinusoidal curves or streaks on the articles. Irregular streaks are more characteristic of natural products such as shell. However, this invention includes any acircular cams and is not limited to irregular-cut cam perimeters, since for some decorative purposes sinusoidal curves might be desirable. It is obvious that other methods of providing transverse oscillation can be provided and these are deemed to be within the scope of this invention.

The word paint is used in its broad sense in this specification and the appended claims and is intended to include lacquers, finishes and the like.

We claim:

1. in a machine for mask-less decorative painting an endless movable skeleton belt comprising two parallel endless chains with a plurality of transverse bars mounted between said chains and having an upper position'in which it moves in a rectilinear path, a plurality of clamping fixtures each mounted on one of said bars, and at least one spray gun assembly positioned above said upper position of said belt; said spray gun assembly comprising a rod which is oscillatable transversely to said path, on which is mounted a downwardly directed spray and which cooperates with a rotatable cam and a spring urging said rod against said cam, so that rotation of said cam causes said spray gun to oscillate transversely to said patch.

2. in a machine for mask-less decorative painting an endless movable skeleton belt comprising two parallel endless chains with a plurality of transverse bars mounted between said chains and having an upper position in which it moves in a rectilinear path, a plurality of clamping fixtures each mounted on one of said bars, and a plurality of spray gun assemblies each positioned above said upper position of said belt; each of said gun assemblies comprising a rod which is oscillatable transversely to said path, on which is mounted a downwardly directed spray gun and which cooperates with a rotatable cam and a spring urging said rod against said cam, so that rotation of said cam causes said spray gun to oscillate transversely to said path; each of said gun assemblies being so constructed and positioned as to cover a controllable defined area on an article held by said clamping fixture.

3. In a machine for mask-less decorative painting an endless movable skeleton belt comprising two parallel endless chains with a plurality of transverse bars mounted between said chains and having an upper position in which it moves in a rectilinear path, a plurality of clamping fix tures each mounted on one of said bars, and a plurality of spray gun assemblies positioned above said upper position of said belt; each of said gun assemblies comprising a rod which is oscillatable transversely to said path, on which is mounted a downwardly directed spray gun and which cooperates with a rotatable cam and a spring urging said rod against said cam, so that rotation of said cam causes said spray gun to oscillate transversely to said path; each of said gun assemblies being so constructed and positioned as to cover a controllable defined area on an article held by said clamping fixture; said fixture comprising a stationary portion and a movable portion spring-connected to and slidable on said stationary portion and cooperable with a fixed cam mounted on the frame of said machine; said stationary portion containing spring activated jaws for clamping the article; said movable portion containing ejector rods cooperable with the article held by said jaws so that engagement of said movable portion with said fixed cam causes said ejector rods to eject the article from said jaws.

4. In a machine for mask-less decorative painting an endless movable skeleton belt comprising two parallel endless chains with a plurality of transverse bars mounted between said chains and having an upper position in which it moves in a rectilinear path, a plurality of clamping fixtures each mounted on one of said bars, and a plurality of spray gun assemblies positioned above said upper position of said belt; each of said gun assemblies comprising a rod which is oscillatable transversely to said path, on which is mounted a downwardly directed spray gun and which cooperates with a rotatable cam and a spring urging said rod against said cam, so that rotation of said cam causes said spray gun to oscillate transversely to said path; each of said gun assemblies being so constructed and positioned as to cover a controllable defined area on an article held by said clamping fixture; said fixture comprising a stationary portion and a movable portion springconnected to and slidable on said stationary portion and cooperable with a fixed cam mounted on the frame of said machine; said stationary portion containing spring activated jaws for clamping the article; said movable portion containing fixed ejector rods cooperable with the article held by said jaws so that engagement of said movable portion with said fixed cam causes said ejector rods to eject the article from said jaws; said fixture containing a shield normally covering said ejector rods and said jaws; means being provided to wipe said shields after ejection.

References Cited in the file of this patent UNITED STATES PATENTS 720,594 Macarthy Feb. 7, 1903 1,932,215 Johnson et a1. Oct. 24, 1933 2,218,811 Chaussabel Oct. 22, 1940 2,261,138 Bullerjahn Nov. 4, 1941 2,587,284 Brewer et a1 Feb. 26, 1952 2,698,597 Buck Jan. 4, 1955 

